Gel Packs....

It might have also been the brand.  For example, some people swear by clif shots or Hammer Gel, but both of those brands make me want to puke. 

I really like Powerbar Powergel and Cranksports Egel - but others hate them.

Or, it could be flavor.  Keep me AWAY from vanilla or chocolate while working out, bring on the fruit flavors, baby.  Other people - ugh, that apple stuff tastes like crap, give me chocolate any day.

Some people like to water them down too - put them in a gel flask, add some water, shake, so the consistency is thinner - me, I like them straight out of the packet.

I'd suggest trying a few different flavors/brands until you find the one you like the best.  Then, just hope they don't stop making them.

What type of gel was it.  I know that Clif Shot and Power Gel make me want to puke due to the consistency.  I love Hammer gel and can tolerate Gu's.

Adios
Dave

Not your grocery store.  Try your local bike shop, running shop or maybe sporting goods store.  Sometimes smaller health food type stores will carry them.

But mostly, some type of athletic store is where you want to be.  Buy one each of different flavors/brands you think you might like and give them all a try.  Once you've found one you like, shop for them online and buy them by the case.  It'll be a lot cheaper unless you happen to get them on sale at your local store.